The Respironics chin strap is designed to hold your mouth closed during CPAP treatment. This chin strap attaches to your CPAP mask headgear using four square velcro tabs. You'll need to use at least two of the velcro tabs to attach to your headgear, and you can use all four if your headgear design permits, and if all four are necessary for a good fit.
This chin strap works with any CPAP mask that has a standard neoprene-like headgear strap. If you happen to have a CPAP mask that has just a silicone rubber strap as a headgear strap (like the old, discontinued Fisher & Paykel Infinity) then this chin strap won't work for you.
CPAP chin straps help to improve therapy by ensuring that breathing occurs through the nasal mask.